text: However, while alarm signals can be coupled with receiver monitoring, there is a lack of consensus on the definition, starting age, and purpose of monitoring. It is either defined as the use of three subsequent gaze alternations, from a threat to a nearby conspecific and back to the threat, or as the use of two gaze alternations. Moreover, while some studies only report gaze alternation as starting in late juveniles, other studies report gaze alternation in infants as early as five months of age. In infants and juveniles, it is potentially a means of social referencing or social learning through which younger chimpanzees check the reactions of more experienced conspecifics in order to learn about new situations, such as potential threats. It has also been proposed to be a communicative behaviour or simply the result of shifts in attention between different environmental elements.